The present invention relates generally to the field of dental implants and, in particular, to a new and useful soft-tissue preservation temporary in the form of a shell, with an immediate-implant abutment and a biologically active surface design that will promote soft-tissue attachment and adhesion according to the biologic and functional anatomic arrangement to the surface of the hollow-shell temporary abutment.
General Considerations and Problems to Overcome:
The tooth is a structure of the oral cavity which is vital to the capability of chewing and important to the general well-being and appearance of people. Anatomically, the tooth resides within the oral cavity, firmly anchored within the upper and lower jaws (maxilla and mandible). Human teeth reside within two distinct anatomic regions of the jaws; the apical inferior portion of the tooth (the root) is connected to the jaw via an attachment called the periodontal ligament. We will here define this portion of the tooth that is connected to the bone as the “bone-zone” or hard tissue zone of the tooth. Second, the superior portion of the tooth (the anatomic crown) is connected to the jaw in the soft-tissue or gingival region of the jaw defined as the “tissue-zone” or soft tissue zone. The anatomic crown is demarcated as that portion of the tooth superior to crest of bone and it will include a small portion of the root superior to the crest of bone as well as the clinical crown that is visible. The tissue-zone forms a soft-tissue collar around the neck of a tooth.
This tissue-zone connection (i.e. soft-tissue to tooth attachment) is composed of three basic anatomic structures of the dento-gingival fiber complex. They are defined as:
(1) the gingival sulcus that is lined by sulcular epithelium;
(2) the junctional epithelium; and
(3) the dento-gingival fibers (a.k.a., the gingival connective tissues).
The gingival sulcus is lined by the sulcular epithelium, a thin non-keratinized stratified squamous cell epithelium without rete pegs. The length of the sucular epithelium is 1 mm to 3 mm in height (on average 2 mm), and approximate the smooth surface of the enamel. The sulcular epithelium extends from the junctional epithelium to the crest of the soft-tissue free gingival margin. The sulcular epithelium is extremely important since it acts as the first line of defense from invasion of micro-organisms into the oral cavity. Maintenance and preservation of this structure is important. The sulcular epithelium acts as a semi-permeable membrane that keeps infecting bacteria by-products from migrating into the underlying connective tissue.
The junctional epithelium consists of a collar-like band of stratified squamous non-keratinized epithelium. It is three to four layers thick in early life but increases to 10 to 20 layers in later decades of life. The junctional epithelium is composed of two grouped states; the basal layer facing the connective tissue and the supra-basal layer extending to the surface of the tooth, creating an attachment/adherence to the enamel surface. The length of the junctional epithelium ranges from 0.25 mm to 1.35 mm (on average 1 mm) and a thickness of 10 to 29 cells wide to one or two cells in its apical termination, located at the cemento-enamel junction. The junctional epithelium is attached to the tooth surface (epithelial attachment) by means of an internal basal lamina to the unexposed enamel surface. It is attached to the gingival connective tissue by an external basal lamina that has the same structure as other epithelial-connective tissue attachments found elsewhere in the body.
The internal basal lamina of the junctional epithelium consists of lamina densa (adjacent to the enamel) and a lamina lucida to which hemidesmosomes are attached. Hemidesmosomes have a decisive role in the firm attachment of the cells to the internal basal lamina on the tooth surface. Hemidesmosomes may also act as specific sites of signal transduction and thus may participate in regulation of gene expression, cell proliferation, and cell differentiation. Hemidesmosomes attachment has been shown to occur on a textured surface. The attachment of the junctional epithelium to the tooth extends apical to the dento-gingival fibers, which produce a true functional attachment of collagen fibers to the surface of the tooth to the gingival connective tissue. All the structures thus far described (Sulcular Epithelium, Junctional Epithelium and the Dento-Gingival Fibers) are coronal or above (supra-crestal) to the bone.
The Dento-Gingival connective tissue is composed of dento-gingival fibers and connective tissue. The dento-gingival are composed of collagen fibers that surround the tooth on the facial, lingual and interproximal surfaces. The length of the supra-crestal dento-gingival fiber zone ranges from 1 mm to 3 mm and is on average 2 mm. The fibers are embedded in the surface of the root of the tooth that is coronal to the crest of bone. The supra-crestal dento-gingival fiber zone extends from the inferior aspect of the junctional epithelium to the superior aspect of the bone crest. The supra-crestal fibers that attach into the surface results from a cellular and an extracellular compartment composed of fibers and ground substance. The ground substance fills the space between the fibers and cells, is amorphous and has a high content of water. It is composed of proteoglycans, mainly hyaluronic acid and chondroitin sulfate, and glycoproteins, mainly fibronectin. The fibronectin binds fibroblasts to the fibers and to other components of the intercellular matrix, enabling cell adhesion and migration. Laminin, another glycoprotein found the connective tissue zone matrix serves to attach it to the surrounding cells. Three types of connective tissue fibers are found, collagen, reticular and elastic and are arranged with specific orientations to the surface of the tooth. The soft-tissue zone stability is established by the attachment of the fibers to the surface, this is a key factor to limiting the apical migration of the junctional epithelium. If the junctional epithelium was to migrate apically it would alter the functional attachment with negative outcomes as is seen during periodontal diseases. Therefore, re-establishing the dento-gingival zone of attachment is critical to the long-term stability and health of the dento-gingival complex (and soft-tissue zone).
With reference to FIG. 11, the three zones are described as Sulcular Epithelium 202, Junctional Epithelium 204, and the Dento-Gingival Fibers 206 and are noted about the parts of a natural tooth 102 with its root 104 in a bone socket 106 of a patient's jaw bone 112. The three zones 202, 204 and 206 are in a soft tissue socket 108 that will be left after tooth 102 is extracted. The soft tissue zones follow a peak and valley shape that mimics the scalloped contour of the free-gingival margin in gum or gingival 110 found around teeth. The peak and valley contour of the free-gingival margin is consistent with a peak and valley contour of the underlying bone around teeth when viewed from the buccal or lingual aspect. It is commonly understood that peak are higher (more coronal) between teeth and on the direct surface of the tooth the valley is (more apical). The differential between peak and valley is typically 3 mm to 6 mm depending upon the tooth under discussion. Anterior teeth display a greater peak to valley contour and posterior teeth display less of this peak to valley height. The peak to valley contour is commonly understood in dentistry as the “scallop” of the free gingival margin. Once again, the soft-tissue contour is reflective of the underlying bony shape and contour. The hollow shell herein described is designed with the naturally occurring peak to valley contour. Each zone described above follow the peak to valley contour on the natural tooth and therefore a hollow shell which is designed to preserve the anatomic configuration of the soft-tissue zone should provide a means to support and allow reattachment to each of these three soft-tissue zones described. The hollow shell herein disclosed provides a specific structure for each soft-tissue zone to enable reattachment/adhesion for that zone. Additionally and importantly each zone noted on the hollow shell is designed with a peak and valley configuration so that each given soft-tissue zone is matched to that zone found nature.
The soft tissue zone (or tissue zone) connection plays a critical role in maintaining health of the oral cavity. It does this by preventing the ingress of microbes and foreign substances into the body by providing a “biologic-seal” at the interface of the tooth-jaw connection at the tissue-zone through the adhesion/attachment of the sulcular epithelium, junctional epithelium and gingival fibers. This functional attachment of the soft-tissue to the surface of the tooth should be fully appreciated as a critical defense barrier. As without the presence of this soft-tissue biologic seal the underlying bone would be vulnerable to numerous invasions of various foreign substances.
In addition, the tissue-zone plays an essential role in maintaining and preserving the dental esthetics of the smile. This same tissue-zone represents the peaks (papillae) and valleys of the soft-tissue gingival that surround the neck of each and every tooth. These peaks and valleys have been defined for the hollow-shell temporary implant abutment herein referenced as our previous U.S. Pat. No. 8,425,231.
It is the spatial relationship of tooth form and color with healthy soft-tissue gingival architecture that are known as the essential building blocks of dental esthetics as we know it. Experts of dental esthetics have called the soft-tissue gingiva “the frame” of the picture, and regard the teeth as the “subject matter” of that painting. Disregarding the frame of a painting would certainly impact the overall esthetic appearance being viewed, and the same is true with respect to the gums and teeth. The loss or the alternation of anatomic structures of the tissue-zone has been shown to lead to an inferior esthetic outcome in addition to causing a potential risk of disease for the patient.
The tooth and its attachment to the jaw is subject to numerous pathogens over the lifetime of a patient, particularly due to trauma/fracture, endodontic failure, decay, localized periodontal disease, etc. Any of these conditions can lead to the eventual need for removal of either a single tooth or multiple teeth. The removal or extraction of a tooth or teeth will result in a radical morphologic change to the anatomy as well as the potential exposure of the internal tissues (connective tissues and underlying organs) of the body to invasion by foreign substances.
The extraction of a tooth results in a cascade of changes depending on how this procedure is performed. Tooth removal in the past has been a highly traumatic surgical procedure. It was not uncommon for an oral surgeon to fully reflect the gingival tissues as a surgical flap to expose the underlying tooth and bone to aid in the ease of access and visualization of the tooth to be removed. It is during this surgical reflection of the gingival soft-tissues that the normal anatomy of the tissue-zone would be radically altered and permanently changed. Destruction of the normal architecture of the gingiva occurs as surgical instruments were used to cut, tear, crush and rip the attachment fibers between the tooth and soft-tissues of the tissue-zone. In accordance with gingival surgical flap surgery, closure of a surgical flap is accomplished with the placement of sutures to close the wound created. Primary (or complete) flap closure is highly desirable to ensure the re-establishment of a biologic-seal of the soft-tissue to prevent ingress of foreign bodies to the host.
Gingival flap surgery also has the known deficiency to result in bone loss from the stripping away of the periosteum and hence the blood supply to the bone during the reflection of a surgical flap. It is well documented in the dental literature that gingival surgical flaps result in bone loss by the exposure of the underlying bone. Dr. Lindhe and co-workers have scientifically demonstrated that surgical flap elevation and removal of teeth leads to loss of the residual bone and the shape of remaining ridge after tooth removal. These undesirable anatomic changes to the bone make the placement of implants more complex and increases risk for patients.
For the reasons identified above, the trend toward minimally invasive surgical procedures has been developed toward the extraction of teeth. Examples of these changes include the use of micro-surgical instruments, periotomes and extraction forceps that do not require the reflection of a surgical flap to remove teeth. Ultrasonic (piezo technology) surgical instruments, dental lasers and rotary devices have been suggested as mechanisms to minimize trauma during the removal of teeth. It is generally accepted within the profession that a minimally invasive technique for tooth removal should be the standard of care.
In an attempt to minimize detrimental anatomic changes during the surgical removal of a tooth, a major effort is now underway to preserve the bone-zone and tissue-zone after tooth removal. The objective of the dental profession to preserve bone was a natural extension of a vast body of knowledge recently created on periodontal bone regeneration via the use of bone replacement substances. Examples of such efforts include autografts, allografts, xenografts and a variety of bone replacement materials that include; Bone Morphogenic Proteins (BMP's), Stem Cell Derivatives, Platelet Rich Proteins (PRP's) derived from the blood and numerous other biologic sources. Bone regeneration after periodontal disease is well established in the prior art. A deficiency of using bone replacement substances, are the inability to contain and protect these materials to exposure to the oral cavity during the critical healing phase, i.e. a fundamental inability to re-establish the all-important biologic-seal of the Tissue-Zone once a tooth is removed.
The use of barrier membranes for guided tissue bone regeneration (GTR) is known attempts to preserve and regenerate lost bone after periodontal disease. The use of membranes has more recently been applied to the regeneration and preservation of bone after tooth removal. Barrier membranes assist in creating a protective barricade to the bone-zone by excluding unwanted cells (connective tissue cells) to the healing site. This is an attempt to allow the body to more effectively refill a residual bony socket with bone cells (a.k.a. osteoblasts) known to be critical for bone growth. A general deficiency of using barrier membranes is the direct exposure of a barrier membrane that consequently lends to the inability to establish a soft-tissue seal. The exposure of the barrier membrane leads to plaque accumulation on the surface of the membrane that is impossible to clean. Once membranes become exposed to the oral environment, bacteria colonization on the surface of the membrane quickly spearheads an infection and/or failure of regeneration of bone. The primary cause of the exposure of the membrane is a lack of a soft-tissue biologic-seal after gingival flap surgery. The inability to re-establish a biologic-seal after the removal of a tooth has many repercussions to bone and soft tissue regeneration.
Loss of the biologic-seal of the tissue-zone also has a significant impact on soft-tissue changes to both the macro- and micro-anatomy of the gingiva. It is accepted in the dental literature that the loss of gingival attachment within the tissue-zone leads to the irreversible loss of the interdental papillae and the gingival architecture surrounding a tooth. There are currently no predictable surgical techniques available to correct the gingival changes to vertical height and horizontal dimensional after tooth removal. Much effort has been directed toward preserving the bone after tooth removal but far less effort has been applied to preserving the macro- and micro-anatomy of the tissue-zone after tooth removal.
As previously noted, the dento-gingival fiber complex plays a vital role in the protection of the host from foreign micro-organisms. The re-establishment of a biologic-seal that reconstitutes the macro- and micro-anatomy of the dentogingival complex is therefore essential to the long term maintenance of optimal health of the oral cavity and consequently the individual. Mechanical attachment of the underlying tissues to a tooth or abutment-implant tooth replacement within the tissue zone is facilitated by the cells of the dentogingival complex (sucular epithelium, junctional epithelium and gingival fibers).
A combination of focal points of adhesion contact, hemidesmosmal adherence/attachment and finite collagen fiber bundles, play a key role in the attachment interface. Histochemical evidence for the presence of neutral polysaccharides and the production of luminin provide an important contribution to the attachment interface at the level of the junctional epithelium. The gingival fiber attachment is composed of collagen fibers, fibroblasts, vessels, nerves and extra-cellular matrix. The bi-layer of the connective tissue; of the papillary layer subjacent to the epithelium and the reticular layer contiguous with the periosteum also contribute to a functional interface and hence the biologic seal found in the tissue zone. Maintenance of the attachment and/or adhesion of the soft tissue cells to the tooth surface are regulated via inter-cellular signaling (transduction) of the undifferentiated and differentiated cells, such as fibroblasts, cementoblasts, endothelial cells, as well as, the hemidesmosmal cells of the soft tissues.
As will be explained more fully in the following, the new method and arrangement of the present invention is an effective means to preserve anatomic architecture of the tissue-zone after tooth removal and a means to re-establish the adherence and attachment of the adjacent soft tissue via a biologic seal at the time of an immediate placement of a dental implant. In addition, the present invention describes a means of providing a biologic surface onto an abutment to which the biologic seal is promoted and can be re-established.
The understanding of using a minimally invasive technique as well as re-establishing a biologic-seal after tooth removal has been discussed but has not yet been made possible in all cases by known methods and apparatuses. In addition to these important concepts one further concept related to tooth removal is the technique of immediate dental implant placement after the extraction of a tooth/teeth and the ability to provide a surface texture, surface or biologically active layer upon the surface to promote re-establishment or new attachment/adhesion to the surface of the implant abutment.
The replacement of a tooth by a dental implant device is well known in the prior art. It is understood that there are two basic components to the dental implant device; the root-form component held within the bone-zone commonly referred to as the “dental implant” and a second component, the implant anatomic crown composed of an abutment and clinical crown. Both the abutment and clinical crown are typically placed superior to the crest of bone therefore within and superior to the tissue-zone. An implant prosthesis was first described as a surgical method and device that used a fully submerged, non-loaded healing period prior to the connection of the dental implant crown.
The advent of contemporary implant dentistry was first described by Prof. P. I. Branemark in the late 1970's and established the use of a titanium root-form screw to be inserted into the bone placed by using an atraumatic surgical technique described by this researcher/inventor. The method described by Branemark discussed the placement of the dental implant into jawbone of a fully edentulous ridge. He described a method in which the implant would be fully submerged and non-loaded during a healing period of 4-6 months after the dental implant was placed and covered within the bone. Pre-operative conditions therefore required a fully healed ridge in which teeth were previously removed. The method of using a submerged, non-loaded healing period for dental implants remains an approach still widely utilized today.
However, over the past 30 years alternative methods to implant placement have occurred. The following are different methods that have been advocated to the non-submerged, non-loaded implant healing technique.
Advantages and disadvantages will be briefly discussed for each technique.
Delayed, Submerged, Non-loaded Implant Placement Method:
Defined as the method for placing a root-form dental implant into the jawbone. The implant is placed within the bone-zone initially. The pre-operative condition requires an edentulous ridge. The technique describes the placement of the implant into the bone at or below the crest of bone and it is fully covered by primary flap closure. An initial healing for a period of 4 to 6 months is required. A second surgery is required to expose the root-form implant and to connect a healing abutment. Second healing period of 2-3 months is required for soft-tissue. Final crown delivery occurs approximately 9 months after the start of treatment.
Deficiencies of this Method:
1. Requires multiple surgeries prior to implant crown placement.
2. Requires an edentulous ridge prior to implant placement into the bone-zone resulting in the irreversible changes to the soft-tissues of the tissue-zone.
3. Difficult to re-establish a biologic-seal after numerous surgeries and the connection of the implant crown.
4. Increased cost because of multiple surgeries and prosthetic components.
5. Previous implant system provided a bone-zone solution to osseo-integration of a root form implant within the bone. These systems were not designed with a separate component that is devised to re-establish the soft-tissue zone connection in the immediate implant placement.
6. Does not provide a suitable surface adjacent to the host soft-tissue zone (dentogingival complex) to promote or re-establish a biologic seal during the extraction and immediate implant placement.
Delayed, Non-submerged, Non-loaded Implant Placement Method:
Defined as the method for placing a root-form dental implant into the jawbone exemplified by the Straumann, ITI implant company. The implant is placed within the bone-zone initially. The pre-operative condition requires an edentulous ridge. The technique describes the placement of the implant into the bone at or below the crest of bone or within the tissue-zone. A transmucosal healing cap component is used. A healing abutment or “cap” is placed onto the implant that is in direct contact with the soft-tissue during the initial bone-healing period of 4 to 6 months. A second surgery is not required to expose the root-form implant. Reformation of the tissue-zone is required. A connection between the implant and the healing abutment is within the tissue-zone.
Deficiencies of this Method:
1. Requires an edentulous ridge prior to implant placement into the bone resulting in the irreversible changes to the soft-tissues of the Tissue-Zone.
2. Requires flap surgery to place dental implant.
3. Difficult to re-establish a biologic-seal after surgery and the connection of the implant crown.
4. Difficult to re-establish soft-tissue anatomy to the state it was prior to tooth removal.
5. Healing abutment has a connection interface within the Tissue-Zone, which allows bacteria to adhere impeding wound healing.
6. Increased cost because of multiple components.
7. Does not provide a means to maintain the original soft tissue architecture while affording a suitable surface for re-attachment at the time of tooth removal and immediate implant placement.
Immediate Root-form Implant Placement:
A recent trend in implant dentistry that has occurred, that overcomes the deficiency of requiring multiple surgeries, is the immediate placement of a root-form dental implant directly into an extraction socket after tooth removal.
This method deviates from the original protocols established by Branemark and co-workers. The advantage to the simultaneous placement of a root-form dental implant after tooth removal is the reduction of the number of clinical procedures required as well as decreased treatment time. This technique eliminates the need to have the bone ridge healed after tooth removal consequently requiring fewer surgical procedures.
Immediate implant placement requires a mechanical locking of the root-form dental implant into the residual socket-site after a tooth has been removed. Mechanical locking refers to the root-form implant engaging undisturbed bone in an attempt to provide primary mechanical stability of the implant within the extraction socket. Immediate implant placement is highly desirable in comparison to delayed implant placement since it allows the immediate replacement of the tooth at a substantially reduced amount of time when compared to previous method of delayed implant healing.
Immediate Implant Placement Presents Numerous Risks and Deficiencies with Current Methods Used:
1. An inability to fully engage the entire remaining socket surface after tooth removal, thereby leaving a space (gap) between the surface of the implant and the surface of the remaining bone.
2. An inability to establish a biologic-seal to the overlying soft-tissues after a tooth has been removed.
3. An inability to retain bone regenerative materials if a residual gap remains between the surface of the implant and the bone socket.
4. An inability to establish a biologic-seal of the soft-tissue over a barrier membrane to protect and contain bone regeneration materials and the blood clot.
5. Inability to preserve the soft-tissue architecture of the gingival of the Tissue-Zone.
6. Inability to promote and/or re-establish a cellular and soft-tissue attachment and/or adherence of the adjacent soft-tissue zone defined as the dentogingival complex to the surface of the an immediate implant abutment.
The deficiencies of achieving a predictable and esthetic long term outcome when using an immediate implant placement protocol can all be directly attributed to the inability to establish an acceptable soft-tissue adaptation that creates an effective biologic-seal, one which re-establishes a true histological and biochemical attachment in the tissue-zone of the remaining soft-tissue socket after removal of a tooth.
Immediate implant placement of a root-form dental implant has been shown to effectively osseointegrate by numerous authors (reference included herein). The residual gap that is present between the implant surface and the bone surface requires careful management whether a surgical flap is performed or a non-flapless minimally invasive extraction technique is used. In either of these two approaches, irreversible soft-tissue changes have been shown to occur with immediate implant placement after tooth removal. Changes within the tissue-zone are shown to occur as early as several hours to more extensive changes over several days after the immediate implant placement.
Numerous authors (reference included herein) have discussed the use of a biologically active surface and the importance of a soft tissue attachment of a medical (dental) implants (e.g., stents, dental implants, canulas and the like). Areva, et. al. (2004, J Biomed Mater Res., 70A: 169-178) described the use of a non-resorbable reactive tetraisopropyl orthotitanate layer (i.e., sol-gel derived nano-porous titainia coating) dissolved in absolute ethanol. A second solution of Ethyleneglycol monoethylether deionized water and fuming hydrochloric acid (HCL, 37%) dissolved in ethanol. The two solutions are mixed and aged for 24 hours and used as a dip-coating process on a titanium substrate. The detailed process described by Areva and co-workers as a “sol-gel derived titania coating” used to produce a soft tissue attachment. Their histo-morphological and chemical analysis using scanning electron microscope equipment demonstrated a good adherence and direct soft tissue attachment of the treated surface.
Rossi, et. al., in a subsequent publication (Peri-Implant tissue response to TiOxide surface modified implants. Clin Oral Impl Res. 19, 348-355, 2008) described the use of a TiOxide thin film layer applied to a smooth implant surface promoting a hemidesmosome attachment. This animal study demonstrated histological and histomorphometric arrangements of the sucular epithelium, junctional epithelium and gingival fibers with direct contact and attachment to the surface of the implant when treated with a thin film TiOxide applied layer. Within the limitations of this study it can be concluded that a non-porous TiOxide surface offers good soft tissue attachment around root form implants.
In addition to the application of a biologically active surface noted above, numerous researchers have discussed the benefits of altering surface properties of an implants with respect to the micro- and macro-morphology of the surface of implants to promote attachment to the implant surface. Such examples relate to laser etching, roughness and texture. Ricci and co-workers (Key Engineering Materials, Vols 198-199; 179-202.2001) describe the effects of textured surfaces on colony formation by fibroblasts and effects of controlled surface micro-geometries. Based on this research a laser micro-grooved surface was tested. Specific size ranges were applied producing a controlled micro-geometry to enhance bone and soft tissue integration. Subsequent studies by this team lead to the development of a patented laser micro-grooving surface morphology (U.S. Pat. No. 6,419,491 herein referenced). Laser micro-grooving surface texture has demonstrated increased soft tissue adhesion and attachment to the surface of titanium dental implants. Other surface characteristics such as hydrophilicity and the use of depositing non-toxic salt residue on a roughened surface of the implant has been described (U.S. Pat. No. 8,309,162 to Charlton, et. al.). Charlton and co-workers described an acid-etched roughened surface with an array of microscale irregularities having peak-to-valley heights not greater than 20 microns. A method of applying discrete hydroxyapatite nano-crystals on the roughened surface exposed to a solution comprising non-toxic salts to promote cell attachment is disclosed. In the same patent, a method of increasing the hydrophilicity by depositing a non-toxic sodium lactate salt residue on the surface of a dental implant to be implanted into living bone promoting improved osseo-integration (cellular attachment) is claimed and described.
Liu, et. al, U.S. Pat. No. 7,341,756 describe applying a multi-layer derived alkoxide on a substrate having a dimension suitable for an implant and forming a second coating layer on the first coating layer that promotes osseointegration. The patent further describes the multi-layer surface applies sol-gel processing to produce a nanometer scale of calcium phosphate (e.g., HA) ultrathin-coating. The bioactive surface of the multi-layer surface coating accelerated osteoblast adhesion and may generate improved osseo-integration of implants within bone. Results of such a surface coating indicted that genes associated with bone formation (co11, OPN, OCN) were unregulated with the multi-layer surface described.
Other Prior Art:
U.S. Pat. No. 5,417,568 to Giglio discloses a dental prosthesis that is said to accommodate the gingival contours surrounding the implant prosthesis by imitating the gingival contours around natural teeth. Since the abutment is rigidly connected to the implant and must always be axially aligned with the long axis of the implant, the abutment will rarely, if ever, closely engage the entire existing soft-tissue socket created when a tooth has been extracted; consequently, inadequate soft tissue socket adaptation exists. Moreover, seldom is the axis of the implant exactly aligned with the axis of the soft-tissue socket. Also, although the abutment disclosed by this patent has raised ridges around its outer perimeter, it is symmetrical, and therefore does not mimic the asymmetric anatomy of a soft-tissue socket in the gingiva of a patient from whom a tooth has been extracted.
Nowhere in the prior art or in current dental implant wisdom is an anatomically shaped and sized abutment in the form of a hollow, asymmetric tubular shell used in conjunction with a dental implant, which is not rigidly or concentrically connected to the implant in advance. As a result of the invention here disclosed, the shell can be moved and maneuvered to any orientation in the x-, y- or z-axis in a soft-tissue socket to effectively and fully engage the tissue-zone with no space or gap between the outer surface of the shell and the soft-tissue socket, independent of the position and axial orientation of the implant in the bony socket. The mechanical de-coupling of the abutment shell from the implant is one of several important advancements of this invention over the prior art.
U.S. RE37,227 to Brodbeck also disclosed a some-what anatomically shaped abutment but again it is axially fixed to an implant so that there is no freedom of movement between the abutment and the implant but rather they are mechanically coupled to each other when being seated in their respective soft-tissue and bone sockets.
An article titled: “Immediate Placement and Provisionalization of Maxillary Anterior Single Implants: A Surgical and Prosthodontic Rationale,” by Kan at al., Pract Periodont Aesthet Dent, 2000; Vol. 12, No. 9, pps 817-824, discloses the building up of an abutment that is fixed to an implant to better match a soft-tissue socket by the addition of autopolymerizing acrylic resin around the abutment by sculpting the outer shape of the otherwise fixed abutment to better fill the soft-tissue socket. This technique also fails to recognize the advantage of mechanically decoupling the abutment from the implant. In addition, the tissue-zone collapses immediately upon tooth removal and extrapolation of its contours by the author is required to recreate as close as possible the soft tissue-zone profile.
Nowhere in the prior art or in current dental implant wisdom is an anatomically shaped and sized abutment in the form of a hollow, asymmetric tubular shell in which a biologically active surface consisting of, but not limited to, surface texture, surface roughness, hydrophilic surface, surface conditioning by applying bio-active agents, creating of a macro- and micro-geometric pattern and/or micro- and macro-morphology surface irregularities (as those previously referenced and described above) to promote the soft-tissue attachment and/or adhesion of the dentogingival complex within the tissue-zone of an immediately placed implant abutment which is capable of making contact with the entire soft-tissue socket when placed upon the immediate implant of the extracted tooth site.
Nowhere in the prior art is a discussion or apparatus that allows a biologically active surface as described above to have intimate contact with the exposed soft-tissue socket immediately after tooth removal and is capable of compensating for eccentric positioning of the dental implant secured within the bone. The apparatus thus provides a means to allow immediate cellular activity from physical contact of the apparatus surface to the direct contact of the soft-tissue surface without the presence of a gap. Additionally, the biologic mediators described above are thus capable of promoting a direct soft-tissue attachment and/or adherence of the implant abutment to the immediate soft-tissue residual socket of the extraction tooth.
Another attempt at accommodating the miss-match between an implant oriented in a bony socket and an abutment positioned in a soft-tissue socket, is suggested in the June 2009 brochure of BIOMET 3i titled “Ideal Solutions For Immediate Aesthetics” that discloses an abutment-implant combination where the abutment axis is at a fixed but non-aligned angle to the implant axis. Here again there is no decoupling of the abutment from the implant so freedom of orientation is not present. Nor is there the suggestion of a biologically active surface that can promote re-attachment of the soft-tissue to the surface of the abutment-implant.